1. Field of the Invention
This invention relates to a position sensor system for facilitating controlling of the operation of a vehicle passenger restraint device and a slidable vehicle seat provided with the position sensor system and, more particularly, to a position sensor system for facilitating controlling of the operation of a vehicle passenger restraint device according to a position of a vehicle seat relative to the vehicle passenger restraint device.
2. Description of the Related Art
Referring now to FIG. 1, a vehicle having a vehicle passenger restraint device such as an airbag module mounted within a steering wheel thereof will be discussed hereinafter in order to facilitate understanding of the present invention.
In the vehicle of FIG. 1, when a slidable seat S is in a forward position relative to an airbag module mounted within a steering wheel H, the deployment of an airbag E is controlled so as to be expedited, and when the slidable seat S is in a rearward position relative to the airbag module, the deployment of the airbag E is controlled so as to be delayed.
Hitherto, it has been proposed that a position sensor system P for sensing a position of the vehicle seat relative to the vehicle passenger restraint device is provided at slide rail means R for the vehicle seat in order to control the operation of the vehicle passenger restraint device. A slidable vehicle seat provided with such a position sensor system is disclosed in U.S. Pat. Nos. 5,967,549 and 6,053,529.
Referring now to FIGS. 2 and 3, the vehicle seat provided with the position sensor system that is disclosed in U.S. Pat. No. 6,053,529 will be discussed hereinafter in order to facilitate understanding of the present invention.
A movable rail 1 is attached to the seat in slidable relationship with a stationary rail 2 that is attached to a floor of a vehicle with L-braces 2a. The position sensor system comprises a sensor flange 3 of a generally L-shape in cross-section projecting laterally from a flange side 1a of the movable rail 1, and a magnetic sensor 4 mounted on a support member 5 extending laterally from the stationary rail 2 for sensing the sensor flange 3 position relative thereto and generating a signal representative of seat position to a processor.
As discussed above, the sensor flange 3 is projected laterally from the flange side 1a of the movable rail 1 and the magnetic sensor 4 is mounted on the support member 5 extending laterally from the stationary rail 2. Therefore, when any products, articles or goods of metal accidentally enter a space between the seat and the vehicle floor, there is a possibility that the magnetic sensor 4 will be interfered by such metal products and work improperly. Further, when any longitudinal products, articles or goods, such as umbrellas, accidentally enter the space between the seat and the vehicle floor, there is a possibility that the sensor flange 3 and/or the magnetic sensor 4 will be deformed and/or damaged by such longitudinal products. Furthermore, since the sensor flange 3 and the magnetic sensor 4 are exposed to the outside, dirt and/or dust may easily adhere onto the sensor flange 3 and the magnetic sensor 4. If dirt and/or dust adheres onto the sensor flange 3 and/or the magnetic sensor 4, there is a possibility that the sensing performance of the magnetic sensor will be decreased.
The position sensor system disclosed in U.S. Pat. No. 5,967,549 includes a magnetic actuator, and a device that is responsive to a magnetic field created by the magnetic actuator. The magnetic actuator is operatively coupled to a guide track affixed to a floor of a vehicle. The devise that is responsive to the magnetic field created by the magnetic actuator is attached to a support rail attached to a seat. In the position sensor system, any construction for protecting the magnetic actuator and the magnetic field-responding device from any products, articles or goods that may accidentally enter a space between the seat and the vehicle floor is not devised. Therefore, when any products, articles or goods of metal accidentally enter the space between the seat and vehicle floor, there is a possibility that the device that is responsive to the magnetic field will be interfered with by such products of metal and work improperly. Further, when any longitudinal products, articles or goods, such as umbrellas, accidentally enter the space between the seat and the vehicle floor, there is a possibility that the magnetic actuator and/or the device that is responsive to the magnetic field will be deformed and/or damaged by such longitudinal products. Furthermore, dirt and/or dust may easily adhere onto the magnetic actuator and the device that is responsive to the magnetic field. If dirt and/or dust adheres onto the magnetic actuator and/or the device that is responsive to the magnetic field, there is a possibility that the magnetic sensitivity of the device will be decreased.
In order to protect each of the above position sensor systems from such external factors as discussed above, any protector means for protecting the position sensor system from the external factors, such as a protecting cover, may be additionally employed. However, this results in an increased number of parts making up the vehicle seat. In addition, such additional protector means will restrict a space surrounding the position sensor system.